Although latex products are well known in the art, an inherent problem associated with these products is the degradation of these products over time due to oxidation which shortens the useful life of the latex product. In the case of natural rubbers, oxidation results in chain scission which in turns causes a gooey, sticky rubber whereas in the case of synthetic rubbers, oxidation results in further cross-linking of the carbon chains which in turn causes a stiff and brittle rubber. It follows that producing a latex product which is more resistant to oxidation would produce a product with enhanced tear resistance, tensile strength, elasticity and a longer useful life.
Latex products are commonly produced by curing a mixture of a polymer or copolymer, an optional stabilizing system and a curing system comprised of an accelerator an activator and a crosslinker.
In order to make the latex product more resistant to oxidation, an antioxidant is also added during production of the latex compound. Mercaptoarylazole compounds have previously been used as antioxidants. However, mercaptoarylazole compounds can also serve as accelerators. U.S. Pat. No. 4,435,532 used 2-mercaptobenzothiazole (col. 4, Example 4) as a heat stabilizer and deemed that “This class of compounds is unusable due to its powerfully accelerating effect on vulcanization since it restricts the possibility of processing the product and does not provide the necessary reliability in operation.”
Surprisingly, the applicant has discovered that combining an anti-oxidant with a mercaptoarylazole compound results in latex products which possess enhanced tear resistance, tensile strength, elongation and a longer useful life.